title: Down-regulation of pituitary gonadotropin secretion in postmenopausal females by continuous gonadotropin-releasing hormone administration.
abstract: Four normal postmenopausal females were infused with synthetic gonadotropin-releasing hormone (GnRH) iv at a rate of 1 microgram/min for 72 h. Serum LH, FSH, and estradiol were measured every 4 h. LH and FSH levels increased from basal values of 23 +/- 3 and 94 +/- 27 mIU/ml, respectively, to peak values of 50 +/- 5 and 145 +/- 9 mIU/ml at 12 h. Serum LH then fell progressively toward basal levels during the continued iv administration of GnRH. Serum FSH fell below basal levels and remained suppressed between 36-72 h of the study period. Serum estradiol remained at levels less than 25 pg/ml throughout the GnRH infusion. Studies of LH and FSH secretion during the continuous administration of GnRH may be a useful model with which to study paradoxical down-regulation of pituitary gonadotropin secretion.
mesh_terms: D005260:Female; D005640:Follicle Stimulating Hormone / Q000378:metabolism*; D007987:Gonadotropin-Releasing Hormone / Q000008:administration & dosage*; D006801:Humans; D007700:Kinetics; D007986:Luteinizing Hormone / Q000378:metabolism*; D008593:Menopause; D008875:Middle Aged; D010902:Pituitary Gland / Q000187:drug effects / Q000378:metabolism*
chemical_list: D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone